Trisomy 12 in B-cell chronic lymphocytic leukaemia: an evaluation of 33 patients by direct fluorescence in situ hybridization (FISH).

An adaptation of the standard fluorescence in situ hybridization (FISH) technique allowing rapid analysis (4 h) has been used to study the prevalence of trisomy 12 in 33 patients with B-CLL, of whom 54% have been shown to have this abnormality. The presence of trisomy 12 has been compared with clinical parameters, and there may be a relationship between the prevalence of trisomy 12 in B-CLL and duration of disease.